Tuesday, January 10, 2012

Math Must Be Believable

Many thanks to my colleague Aostre Johnson for this wonderful cartoon. It does make you stop and think just what was on people's minds thousands of years ago There must have been people with senses of humor back then just as there are now. Perhaps Stonehenge was a practical joke by some wealthy stonemason. What will they make of Carhenge in the year 4012?.

There has been a depressing math story circulating in the media for the past several days that describes how a group of Georgia teachers used the topic of slavery to write math problems for third grade students. As worrisome as the content of the math problems is I find the math involved in the problem just as disturbing.

The problem reads " Each tree has 56 oranges. If 8 slaves pick them equally, then how much would each slave pick?" One of the most important things to consider when writing math problems for children to solve is to make the problem as realistic, meaningful, relevant and grammatically accurate as possible. This particular problem fails in every way.

How could "each tree" have 56 oranges. I'm not a biologist but I would imagine it would be an unbelievable coincidence if each tree in an orange grove had 56 oranges. Why "each tree"? There's an implicit number of trees but it is, somewhat confusingly,  not stated. Why not say "An orange tree"? None of the orange trees that I have seen would be big enough for 8 people to pick oranges at the same time. Would each picker have his/her own ladder or picking tool or would they each take it in turns to pick their oranges? Wouldn't it be one, or maybe 2, pickers per tree? Why would they all pick the same number? If there were 9 oranges close together would one picker pick 7 and then call on another to pick the other two?  Finally, the use of the word "much" is grammatically and mathematically incorrect. Much refers to a continuous variable and not a discrete variable which oranges are. It should be " How many oranges did each person pick?".


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